1. Field of the Invention
The present invention relates to a gas generator for an air bag and an air bag system using the same.
2. Description of Related Art
As a gas generator for an air bag, there are a pyrotechnic-type gas generator in which only a gas generated by combustion of a gas generating agent is used for inflating an air bag, and a hybrid-type gas generator in which a gas generated by combustion of a gas generating agent and a pressurized medium are used for inflating the air bag. In the gas generator for the air bag, ignition means provided with an igniter is employed as means for generating a gas by combusting the gas generating agent, and a single-type gas generator with one igniter and a dual-type gas generator with two igniters are used at present.
In the case of a dual-type gas generator with two igniters, two conductive pins (a center pin and a grounding pin) of the positive electrode and the negative electrode are provided in the respective igniters. By electrifying the respective conductive pins, a priming is ignited and burnt at conductive wires (namely, heat generating wires, electric resistance wires or the like), which connect the two conductive pins, in the course of current flows from the positive electrodes to the negative electrodes and the gas generating agents are burnt, in some cases, through ignition and burning of transfer charges.
As such a dual type gas generator for the air bag, there is one which is adjusted to activate only one igniter or to activate both igniters according to the magnitude of an impact on the vehicle. In this case, it is important that the other igniter is not activated erroneously when the magnitude of impact is relatively small and only one igniter is actuated.